The present invention relates to an information-processing system, an information-processing apparatus, an information-processing method, a recording medium and a program. More particularly, the present invention relates to an information-processing system capable of qualifying terminals included in the information-processing system as terminals allowed to utilize metadata relevant to a content in dependence on the metadata, an information-processing apparatus employed in the information-processing system, an information-processing method adopted by the information-processing apparatus, a program prescribing the information-processing method and a recording medium for storing the program.
In utilization of metadata relevant to broadcast contents in terminals, in dependence on the substance of the metadata, the content-broadcasting enterprise sets forth a requirement to distinguish terminals each having a processing system capable of processing data at a high level of security from terminals each having a processing system incapable of processing data at any level of security. In this case, the broadcast contents include contents distributed by broadcast waves and contents distributed by way of an IP network.
In accordance with such a requirement, metadata to be handled at a high level of security is treated in the same way as a content and protected, stored and subjected to reproduction control by a DRM (Digital Rights Management) in the same way as a content to be handled as a content to be treated at a high level of security. That is to say, metadata to be handled at a high level of security is encrypted by using a content key for encrypting a content in the same way as the content. As an alternative, metadata is encrypted by using a key for encrypting the content key. For more information, refer to patent reference 1: Japanese Patent Laid-open No. 2002-101086.
In actuality, however, metadata is generally treated by execution of a procedure different from that for contents. For example, in a user terminal, a plurality of different kinds of metadata is acquired before a content and stored in a database in advance to be searched prior to utilization in many cases.
That is to say, metadata is decrypted only when the metadata is subjected to reproduction and display control. Thus, unlike a content with protected security, it is not until a request for search of a content that metadata is decrypted and exposed to the user. However, it is difficult to provide hardware for decrypting and exposing metadata not before a request for search of a content is made. Thus, metadata had rather be decrypted and stored in a database in advance.
In order to protect the security of metadata, however, it is necessary to store a database including a plurality of pieces of metadata in an expensive secure memory in advance in the same way as protection of contents. From a hardware point of view, however, it is difficult to store such a database in an expensive secure memory in advance in the same way as protection of contents. In this case, it is possible to provide an apparatus having a configuration in which a database area for storing metadata is added to a tamper-proof secure memory to be used in conjunction with a secondary storage device such as a secure hard disk. In general, however, it is also difficult to procure a secure hard disk due to a high-cost reason. Even if a secondary storage device such as a secure hard disk can be obtained, in many cases, the data-security protection provided by the secondary storage device is inferior to that of a secure memory.
In spite of the fact that it is necessary to handle metadata and contents by separating the conditions themselves for utilizing the metadata and contents in processing carried in a user terminal from each other, the metadata requiring a high level of security protection is treated in a user terminal in the same way as a content requiring a high level of security protection. In consequence, metadata raises a problem of an excessively high cost of handling the metadata or deterioration of the security protection.
In addition, the broadcast-content enterprise imposes a requirement to classify protection of copyrights by metadata type instead of a requirement to distinguish metadata and contents from each other. To put it concretely, the imposed requirement requires that only a terminal offering security protection at the same level as protection of security for contents be allowed to process information such as segment metadata describing that a content is divided into a plurality of segments and only highlight scenes are subjected to digest reproduction. As described above, however, in accordance with the conventional method, metadata is classified only on the basis of whether or not the metadata requires security protection. Thus, the conventional method has a problem of an inability to finely set the level of security for protection of copyrights in accordance with the types of metadata.